Quick-action electric switch



y 3 I A. J. VEALL 1,758,870

QUICK ACTION ELECTRIC SWITCH Filed June 25, 1927 ig/ g a Y-r Patented May 13, 1930 PATENT OFFICE ARTHUR JAMES VEALL, OF MELBOURNE, VICTORIA, AUSTRALIA QUICK-ACTION ELECTRIC SWITCH Application filed June 25, 1927, Serial No. 201,383, and. in Australia July 22, 1926.

This invention relates to improvements in quick action electric switches and refers especially to pull switches of the type usually located on ceilings and operated by pulling on a flexible member such as a cord.

The object of the invention is to provide an electric switch of the quick action type embodying simple and durably constructed mechanism, operable by a pull member,

whereby the contacts will normally have a quick make and break or non-controllable action, and in which provision is made for effecting a positive or controllable action in the event of an occasional defective operation of the parts when the pull cord is actuated.

I accomplish the above-mentioned objects by providing a base of insulating material having fixed contacts fitted thereto, a bridge member fitted to the base, movable contacts oscillatably mounted on the bridge piece, an oscillatable member pivotally mounted on the bridge piece, a spring interposed and exerting pressure between the oscillatable member and the movable contacts, a grooved pulley mounted on the bridge piece and having its periphery disposed approximately tangential to the axis of the switch, an eccentric associated with the pulley, a fork on the oscillatable member engaging the eccentric, a lever mounted about the axis of the pulley and having one end of a flexible pull member secured thereto, means for resetting the said lever after the pull member has been released, and clutch mechanism for causing the pulley F to move in one direction with the said lever.

Means are also provided whereby in the event of the said spring becoming defective the movable contacts will be positively actuated by the above-mentioned oscillatable member or by members fitted thereto.

Having briefly set forth the object and nature of the invention, reference will now be had to the accompanying sheet of explanatory drawings wherein Figure 1 is a view in elevation and partly in section of an electric switch constructed in accordance with the invention.

Figure 2 is a view in sectional side eleva tion taken on the line 22 of Figure 1.

Figure 3 is a view in inverted plan of the switch with the cover removed therefrom.

Figure 4 is a perspective view of a detail of the invention and hereinafter is fully described, and

Figure 5 is a view in elevation of a modified form of the invention.

In the drawings the reference numeral 10 designates a base of insulating material such as porcelain having fixed contacts 11 pro vided with suitable terminal sockets 12 secured thereto.

The base 10 of the switch is also fitted with a bridge piece 13 carrying pivot pin 13' on which is pivotally mounted a stirrup-shaped member 14 having movable contacts 15 secured to, but insulated from, the free and looped end thereof.

A pair of oscillatable members 16 which are rigidly united and retained the requisite distance apart by a distance piece 17 are pivotally mounted on a pin 18 passing transversely through the lower portion of the bridge piece.

A rocker 19 is carried on a stirrup-shaped member 14 and slidably engages one end of a guide member 20, the other end of which is provided with trunnions 21 pivotally mounted in the upper portions of the opposed oscillatable members 16.

A compression spring 22 surrounds the guide member 20 and is adapted to exert a pressure between the oscillatable members and the stirrup 14.

A grooved guide pulley 23 is mounted freely on a hollow axle 24 supported in extensions of the bridge piece 10 and is so arranged that the axis of the switch is disposed approximately tangential to the periphery of the pulley (see Figures 1 and 3).

Eccentrics 23 are formed on the sides of the pulley 23 and are engaged by forks 25 formed in the oscillatable members 16.

A U-shaped lever 26 is arranged to partially embrace the pulley 23 and is secured to the hollow axle 24 by means of a projection 27 thereon (Figure 4) engaging a slot 28 formed longitudinally in the said axle and one end of a flexible pull member 29 consisting of a metallic ball chain is secured to a lug formed on the free end thereof.

The ball chain passes partially around the grooved pulley and the free end thereof depends through a hole 31 formed centrally in an exteriorly screwed stud 32 on the bridge piece.

The hole 31 through which the ball chain 29 passes is flared at its lower end to enable the pull cord to be operated conveniently when pulled at an angle to the axis of the switch.

The free end of the ball chain is secured to a pull cord (not shown) of sufficient length to enable a person standing on the floor to conveniently grasp and operate the same.

A cover 33 provided with a central hole to iass over the screwed stud 32 on the brid e piece is adapted to be retained correctly in position on the base by means of a nut 34 engaging the said screwed stud.

A torsion spring 35 is accommodated within the hollow axle of the pulley -3 and has one of its ends secured to a lug 36 formed 1 on the bridge piece 13 and the opposite end thereof secured to the said hollow axle by means of a screw 36 so that upon the release of the flexible pull member the spring Will return the U-shaped lever to its normal position i. e., the position shown in Figure 1 of the drawings.

In order to provide an operative connection between the J-shaped lever 26 and the pulley 23 carrying the eccentrics 23 so that the pulley will be partially rotated with the U-shaped lever when the flexible member is pulled but will remain stationary during the resetting movement of the lever, the pulley is provided with a transverse hole in which is accommodated a sliding pin 37 adapted to be engaged by one of a pair of diametrically disposed cam-shaped driving members 38 formed on one side of the U-shaped lever 26.

The opposite side of the U-shaped lever is formed with setting came 39 of a shape similar to the driving members 38 but the former are located somewhat in advance of the latter as clearly shown in Figure 4.

In the normal position of the switch mechanism the sliding pin 37 projects from the side of the pulley in advance of one of the above-mentioned cam-shaped driving members 38.

Upon the flexible member 29 being pulled the "Ll-shaped lever 26 is given an initial movement until a driving member 38 engages the projecting portion of the sliding pin 37 thus causing the pulley 23 to move in unison with the said lever during the subsequent portion of its movement.

When the flexible member is released after the operation of the switch the torsion spring 35 resets the U-shaped lever and in order that the driving members may clear the projecting portion of the sliding pin the said members are formed with ramps adapted to push the pin inwardly so that it projects from the opposite side of the pulley 23.

When the resetting movement is almost completed and the second driving member 38 has passed the sliding pin 37 the latter is engaged by one of the setting cams 39 on the Ushaped lever and is projected thereby into the path of movement of the said second driving member 38 ready for a successive operation.

It will be obvious that each operation of the switch causes the pulley 23 and associated eccentrics 23 to make half a revolution thus oscillating the oscillatable members 16 to displace the lower end of the compression spring 22 to open or close the contacts.

Forked extensions to are formed on each side of the stirrup-shaped member 14: and

these are adapted to loosely embrace a transversely disposed pin 41 on the oscillatable members 16 and in the event of the compression spring becoming defective, the movable contacts 15 will be positively operated by means of the said transverse pin contacting with the sides of the forked extensions as will be readily understood.

The sides of the oscillatable member are provided with slots 42 loosely accommodating the pivot pin 13 of the member carrying the movable contacts and the stop pin.

In order to limit the movement of the stirrup-shaped member 1% and movable contacts 15 fltted thereto, a stop pin 42 is fitted to the bridge piece 13 and is adapted to be engaged by the forked extensions of the stirrup when the latter is disposed in either of its extreme positions.

If preferred the oscillatable members 16 may be stamped from a single piece of material and subsequently bent into the requisite shape in lieu of being formed of two separate pieces of sheet metal as shown.

Although the construction above described is preferred because of the symmetry obtained, it will be obvious that if desired only one eccentric 23 and coacting oscillatable member 16 may be employed; similarly one forked extension 40 on the stirrup-shaped member 1 1 carrying the movable contacts will sufflce to coact with the stop pin secured to the bridge and ensure the positive actuation of the switch.

In a modification of the invention (see Figure 5 of the drawings) a centrally pivoted oscillatable lever 43 is pivotally mounted on the bridge piece 13 and its lower end to one end of a link 1 tl e other end of which engages the eccentric 23. The upper end of the oscillatable lever 23 supports the lower end of the guide member 20 for the compression spring 22 and when the said lever" is moved the lower end of the spring is displaced in such a manner as to operate the stirrup 14 carrying the movable contacts 15 in the usual manner.

In a further form of the invention the rocking lever 43 may be dispensed with and the free end of the link 44 can be connected direct to the guide member 20 for the compression spring.

In this construction guide pins are disposed below the link 44 or if desired any other guiding means may be employed whereby the free end of the link 44 may be constrained to move in a substantially horizontal path.

In the above-mentioned alternative constructions the pulley 23 and eccentrics 23 are adapted to be partially rotated in substantially the same manner as that described in connection with Figures 1 to 4 of the drawmgs.

It will be readily understood that numerous small and immaterial modifications may be effected in the construction and arrangement of the parts without departing from the spirit and scope of the invention and I therefore do not wish to be understood as limiting myself to the use of the positive terms employed herein.

Having now described my invention what I claim as new and desire to secure by Letters Patent is 1. An electric switch having a base of insulating material supporting fixed contacts, a bridge piece fitted to the base, movable contacts fitted to a member pivotally mounted on the bridge piece, an axle on the bridge piece, a guide pulley rotatively mounted on the axle, a U-shaped driving member fitted to the axle and partially embracing the pulley, a pull cord passing around the pulley and attached at one end to the driving member, a spring acting on the driving member in opposition to the pull cord, eccentrics associated with the pulley and adapted to be actu- 1 ated in one direction by the operation of the driving member, an oscillatable member adapted to be actuated by the eccentrics, and a compression spring interposed between the oscillatable member and the member carrying the movable contacts whereby when the oscillatable member is actuated by the partial rotation of the pulley by the driving member the compression spring will be displaced to exert an opening or closing pressure on the movable contacts.

2. In an electric switch according to claim 1, ratchet mechanism interposed between the driving member and the eccentrics whereby each oscillation of the driving member will cause the eccentrics and pulley to be rotated approximately half a revolution and the contacts to be opened or closed.

3. An electric switch according to claim 1 wherein the axle supporting the driving member is of tubular formation and houses a torsional spring adapted to return the driving member to its normal position after the same has been operated by the pull cord.

4. In an electric switch according to claim 1, a guide member for the compression spring, trunnions at one end of the guide member pivotally mounted in the oscillatable mem ber, a rocker slidably supporting the opposite end of the guide member, said rocker being carried by the member supporting the movable contact.

5. In an electric switch according to claim 1, a slidable pin mounted transversely in the pulley, a pair of oppositely disposed ratchet teeth on one side of the U-shaped driving member and in the path of movement of the sliding pin, and setting cams on the opposite side of the U-shaped driving member adapted to project the sliding pin into the path of the ratchet teeth when the driving member is returning to its normal position.

6. In an electric switch according to claim- 1, a slidable pin mounted transversely in the pulley, diametrically opposed ratchet teeth on one side of the U-shaped driving member, diametrically opposed setting cams on the opposite side of the U-shaped driving member, said setting cams being arranged in advance of the ratchet teeth.

7. An electric switch according to claim 1, wherein the axle is of tubular formation and the torsional spring housed within the same has one of its ends secured to the axle and the opposite end bearing against the bridge piece.

8. In an electric switch according to claim 1, a pin on the oscillatable member and a forked extension on the member carrying the movable contacts adapted to loosely embrace the pin whereby the movable contacts will be positively actuated, substantially as described.

9. In an electric switch according to claim 1, a screw threaded stud on the bridge piece, a cover having a central hole accommodating the screwed stud, a nut on the stud for retaining the cover in position, and a hole formed centrally in the stud for guiding the pull cord, substantially as described.

10. In an electric switch according to claim 1, a stop pin on the bridge piece and a slot in the oscillatable member loosely accommodating the pivot pin of the member carrying the movable contacts and the stop pin, substantially as described.

In testimony whereof I have signed my name to this specification.

ARTHUR JAMES VEALL. 

